Rubber stripping machine



RUBBER STRIPPING MACHINE Filed May 24, 1943 7 Sheets-Sheet 1 Feb. l5, 1944. R. A SAN'DBERG' RUBBER STRIPPING MACHINE 'l Smets-sheet 2 Filed uay2'4, 194s l .IN V EN TOR.

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Feb. 15, 1944. R. A. SANDBERG 2.341,816

RUBBER STRIPPING MACHINE Filed May 24, 1943 i '7 Sheets-Shel'. 5

. IN VEN TOR.

Feb. 15, 1944. R. A. sANDB'ERs 2,341,816

RUBBER STRVIPPING MACHINE Filed May 24, 194s 'z sheds-sheet 4 vALL i @60' @25a/Mey,

Feb. 15, 1944.

R. A. SANDB'ERG RUBBER STRIPPING MACHINE Filed May 24, 1943 7 Sheets-Sheet 5 INVENTOR. @Z 60 wzoLQ/g Feb. 15, 1944. R. A. sANDBERG 2,341,816

RUBBER STRIPPING' MACHINE Filed May 24, 194s 'r sheets-sheet' 6 9S a .9o 99 92 t A *l I' Z l C i v INVENTOR.

Filed May 24. 1943 Feb. 15, 1944.

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Patented F eb. 15, 1944 RUBBER STRIPPING MACHINE Ray A. Sandberg, Waukegan, Ill., assignor to Burgess-Norton Manufacturing Company, Geneva, Ill., a corporation of Illinois Application May 24, 1943, Serial No. 488,117'

12 Claims.

This invention relates to improvements in machines or apparatus for stripping the rubber from rubber treaded links employed in endless treads for vehicles, such as armored war tanks.

Such rubber treaded links as heretofore used on rubber vehicles each consists of a rectangular metal frame made up of two tubular pivot members rigidly connected at opposite ends by metal cross members, and having a rubber tread molded in a solid block surrounding both tubular pivot members and filling the space between them. Such rubber blocks are subject to rapid wear and to deterioration, and it is frequently desirable to salvage and recondition the metal frames of the links for further use, either by applying a new rubber tread, or, as is now common practice, to replace the rubber tread with meta1 tread surfaces. For such reconditioning, it is necessary to strip or remove the rubber from the metal framework of the link. It has been found extremely diicult to do this either by hand or by machinery because of the peculiar shape of the link, and also the fact that the rubber is extremely tough and resistant to ordinary cutting operations and adheres to the surfaces of the metal framework so as to make its removal very diicult.

The principal object of the present invention is to provide an improved form of machine for stripping or removing the rubber from the metal framework of the link in an eicient, rapid and economical manner.

The machine of the present invention operates upon the general principle of the machine disclosed in the prior application of Clayton O. Dohrenwend, Serial No. 459,625, filed September 25, 1942, now Patent No. 2,327,027, issued August 17, 1943, but includes several features of improvement thereon, as will appear from the following description.

The invention may best be understood by reference to the accompanying drawings, in which- Figure 1 is a perspective view of a tread link of the kind especially adapted for treatment by my improved invention;

Figure 2 is a perspective view of the tread link after it has been operated upon by the machine;

Figure 3 is a top plan view of the machine embodying the features of my present invention, showing a tread link in operating position, and the cutting means in engagement with said tread link;

Figure 4 is a vertical section of the machine taken generally on line 4-4 of Figure '3, but with parts broken-away to illustrate certain details of construction;

Figure 5 is a detail section of the right hand chuck member and associated parts, taken generally on a horizontal plane including the axis of said chuck member;

Figure 6 is a detail section of the left hand chuck member and associated parts, takenl generally on a horizontal plane including the axis of said chuck member;

Figure 7 is a fragmentary view, in part diagrammatic, showing the construction and operation of the chucks and'their associated holding members for securing a tread link while being operated upon by the machine;

Figure 8 is a detailed face view of the right hand chuck and holding member;

Figure 9 is a detailed face view of the left hand chuck and holding member;

Figure l0 is a detail section taken on line lll-l0 of Figure 3;

Figure 11 is an enlarged detail plan View of the carriage and cutting knives mounted therein, with the upper knife in extended position;

Figure 12 is a vertical section of the carriage and knives taken on line lll-l2 of Figure 11, but showing the lower knife in extended position fo the beginning of the scarng operation;

Figure 13 is a detail sectional view somewhat similar to Figure 12, but showing the position of the link after the lower knife has completed its scarng cut in one direction;

Figure 14 is a fragmentary detail section showing the cutting knives in reverse position, ready for initiating the scarl-lng cut in the reverse direction of rotation of the tread link;

Figure 15 is a detail vertical section through the carriage, taken on line |5-l 5 of Figure 11;

Figure 16isa detail perspective view of one of the cutting knives;

Figure 17 is a detail View of the friction brake on the motor shaft;

Figure 18 is a diagram of the electric control system for the machine; and

Figure -19 is a diagram of the fluid control system for the machine.

Referring lrst to the details of construction of the tread links for which my improved stripping process is particularly designed, one of the tread links, indicated at I0, l0 in Figures 1 and 2, is made with a metal base frame consisting of two metal tubular pivot members Il, ll, in parallel spaced relation to each other and. rigidly connected atopposite ends by metal cross members l2, l2, each having eyes I3, I3 at opposite ends thereof, in which the metal pivot members are fixed, as by brazing or welding. Pivot pins l5 extend through each of the tubular members Il, Il, and rubber sleeves i6, i6 are usually interposed between each of said pivot pins l5 and their respective tubular members il, so as to permit a limited torsional movement of the pivot pins in said tubular members.

As the tread link is originally made, a rubber tread is formed by molding the rubber in a solid block around and between the tubular pivot members il, ll, said block terminating short of the outer faces of the metal cross members i2, l2. Figures l and 2 show the condition of the rubber block i1 after its tread surfaces have been worn away by wear to considerable extent. Although the two tread surfaces are usually reversible, they are often subject to such rapid wear that the tread link soon becomes useless and requires salvage or reconditioning for further use.

Owing to the scarcity of rubber, a preferred method of reconditioning now employed consists in replacing the rubber blocks by metal tread surfaces, as previously mentioned. But regardless of whether rubber or metal is used for the tread surfaces, it is desired to remove all of the rubber from the exterior surfaces of the metal frame of each link without harming or disturbing the rubber bushings I5, IE within the tubular members Il, li, and surrounding the pivot pins I5, I5, as previously described. The machine of the present invention is particularly designed for this purpose and details thereof will now be described.

The improved machine of the present invention includes a main frame indicated at 20, having a horizontal bed plate 2l, and a plurality of upright legs or supports 22, 22, having upright side plates 23, 23y suitably arranged therebetween to form a casing for the mechanism below the bed plate.

Two laterally spaced, opposed chuck members 25, 25, are disposed on a common axis extending longitudinally of the bed plate to provide means for securing a tread link therebetween when being operated upon by the machine.

The right hand chuck 25 is fixed on a spindle 21 (see Figure 5), which has bearing in spaced upstanding bearing blocks 29 and 30. Said spindle has a gear 3| keyed thereon. The left hand chuck 2B is xed on the inner end of a spindle 32, which has bearing in spaced bearing blocks 33 and 34 (see Figure 6), and has a gear 35 fixed thereon.

The two gears 3i and 35 are of the same pitch diameter and are driven by similar pinions 35 and 3l, respectively, mounted on a common drive shaft 38. Said drive shaft extends longitudinally along the rear of the bed plate and is journaled in bearing blocks 39 and All. With this gearing arrangement the two chucks are driven in unison on a common horizontal axis.

The drive shaft 38 is driven by an electric motor t! supported on a shelf 42 forming part of the main frame beneath the bed plate. As shown herein, the drive shaft 38 has a chain sprocket 43 fixed on the outer end thereof engaged by a chain 44, which is also trained over a chain sprocket d5 on a shaft Mi. The latter shaft is driven from a worm gear reducer of the usual construction, indicated generally at lll. Said gear reducer is driven from the motor 2i by a shaft 43, which also has a friction clutch 49 associated therewith. The electric motor is of the usual reversible type, so as to drive the chuck members 25 and 26 in opposite directions, as will hereinafter more fully appear.

The chuck members 25 and 26 have means for receiving and automatically chucking the tread links while they are being operated upon by the machine, as shown in detail in Figures 7, 8 and 9. Fixed on the face of the right hand chuck member 25 is a holding member 48', which has a U-shaped slot 49 of such size as to receive the projecting ends of the pivot pins I5, l5, at one end of a tread link in sliding engagement therein. In the base of the slot 49 two recessed bores 50 and 5I are provided, the rst of which is disposed concentrically of the chuck member to receive the end of one of said pivot pins, and the other of which is in off-centered radial relation with said chuck. A spring-pressed plunger 52 projects through an aperture 53 in the base of the recessed centered bore in the holding member 48', and is adapted to engage the adjacent outer end of the centered'pivot pin I5 of the tread link when the latter is mounted in the chuck, so as to serve as a knockout for the tread link when it is released from the chuck, as will presently be described.

The opposite left chuck member 26 has a somewhat similarly designed holding member 55 mounted therein, excepting that in this case the said holding member is slidably mounted in a recess 5t formed in the face of said chuck member, so as to have limited movement axially of the chuck member, as indicated in Figure rI. Two bores 5l and 58 are formed in the face ofthe holding member 55, corresponding to the pin receiving bores 50 and 5l in the right hand holding member 48'.

The slideable holding member 55 is xed, as by a pin 59, to the outer end of a rod B6, which extends axially through the driving spindle 32 of the chuck member 2G and is arranged to be shifted longitudinally by means of a yoke 6| which engages a grooved collar 52 mounted at the outer end of said rod.

The collar 62 is preferably connected to the rod iii) through a yieldable lost-motion device herein consisting of a sleeve 63 fixed on said rod and a coil-spring GQ surrounding said sleeve, having the inner end thereof suitably attached to the flanged inner end 65 of the sleeve S3, and its outer end suitably attached to the collar 62. The spring 64 is relatively stili', so that normally the rod lill will shift with the collar for moving the holding member 55 into and out of chucking relation with the adjacent cross member i2 of the tread link and exert a holding pressure on the tread link when the latter is in fully chucked position between the holding members 55 and fifi. This holding arrangement affords compensation for slight variations in the overall length of the cross members I2, l2, the outer faces of which sometimes become worn from eld service. It also protects the machine against injury if the opposite ends of the tread link may be improperly seated between the opposed holding members 55 and A8'.

The yoke 5 l, which shifts ie holding member through rod El), as just described, is integral with a lever 8'! pivoted on an upright pin l58 suitably iixed on the bed plate 2i. Said lever has its forward end connected by pivot pin 69 to the end of a piston rod 'lil associated with a fluid cylinder l'! mounted above bed plate 2i, longitudinally ci the machine. Power connections for actuating and controlling' the operation of the fluid cylinder 1I will hereinafter be more fully described.

The fluid cylinder 1| also actuates a carriage indicated generally at 12, which is slidably mounted on the front end of the bed plate, for moving the cutting means into and out of operative position relative to the work. The pin 69 on the end of piston rod is connected by a link 13 to the outer end of a rocking lever 14, which extends generally along the front of the bed plate, and is pivoted intermediate its ends on an upright pin 15. Said rocking lever is connected at its inner end to a pin 16 on the carriage 12. Said carriage is guided for its horizontal slidable movement between suitable guides 11, 11, fixed on the bed plate 2| (see Figure 15).

In the preferred form shown herein, the upright pivot pin on which the rocking lever 14 is pivoted, is mounted on a slidable base member 18 which is secured between guides 19, 19, for movement forwardly or rearwardly of the bed plate, to compensate for necessary variations in positioning of the cutting means on the carriage. Adjustment of the base member 18 is accomplished by a threaded rod 89 extending through an annular block 8| fixed to the front end of the bed plate, and having its outer end in position to be engaged for rotation by a suitable tool. The adjusting rod 89 may be supplemented by a pair of bolts 82, 82, which may also extend through the anchor block onopposite sides of the adjusting rod 8U, and are adapted to engage the outer face of the base 18 to resist forward displacement of the latter. The base member 18 also has a rearward extension 18a secured thereto, on which the inner end of the fluid cylinder 1i is pivotally mounted, as by upright pin 1lb (see Figure 3), to permit swivelling movement of said cylinder.

The cutting means for scarfing or removing the rubber from the tread links includes a pair of knives 85, 3B, which are arranged one above the other in longitudinal slidable relation between recessed side walls of a base portion 91 of the carriage, and below a cover plate 88 of the latter. Said knives consist of rear base portions 89 and 99 respectively, which are generally rectangular in shape, and forward ends, which are formed with cutting blades 9| and 92V respectively. The said cutter blades are arranged at mutually reversed angles to each other, shown in the various figures. The arrangement is such that the lower knife 35 may project forwardly when the tread link is being rotated in a clockwise direction, while the upper knife is projected forwardly into cutting position when the-tread link is being rotated in a counterclockwise direction.

The means for shifting the cutting knives alternately into their f respective cutting positions comprises an upright shaft 95, having a pair of eccentrics 99 and 91 intermediate its ends, which respectively engage in transverse slots 98 and 99 formed adjacent the rear ends of the knives 85, 86. Theupper end of the shaft v95 has bearing in the cover plate 88 of the carriage, and its lower end hasbearng in the base portion 81 of said ram, as shown in Figure l2. The shaft 95 is rotated by power means carried on an movable with the ram.

In the form shown, the power actuating means for shaft 95 comprises a fluid cylinder E88 mounted horizontally beneath a projecting front portion of the carriage base, and having a piston rod |91 projecting rearwardly, carrying a rack member Illia thereon for engaging a pinion llb fixed on the lower end of the shaft 95. The rack member lilla has its rear face supported in a guide IIJIc carried by the base portion 81 of the ramasv shown in Figure 15. The means for actuating and controlling the operation of the iiuid cylinder 198 will hereinafter more fully appear.

'Ihe two eccentrics 98 and 91 on shaft 95 are offset from each other at an angle of 180 degrees. Thus, by rotation of the shaft 95, the two eccentrics 9E- and 91 will operate to shift the knives 85 and 85 forwardly and rearwardly in alternate relation with each other. In other words, when the lower knife 85 is projected forwardly, the upper knife 86 willbe withdrawn rearwardly, and vice versa.

In the preferred arrangement, shown in detail in Figures 11, 12 and 13, it will be observed that when one of the knives, as, for instance, the lower knife 85, is in its forwardly projected position, the other or upper knife 86 will be Withdrawn so that its rear face engages the upright Wall 81a of the recess within which the two knives are mounted. In this manner, the .reaction upon the projected knife 85 is carried directly through the lower eccentric 96, the adjacent upper eccentric 91, and the upper knife 86 to the rear wall 81a. Since the latter wall is integral with the base member 81 of the carriage the eccentric shaft 95 will thus be relieved of much of the thrusting pressure which it would otherwise be called upon to withstand. Similarly, when the lower knife S5 is withdrawn and the upper knife projected forwardly, the rear face of the lower knife will engage the upright wall 81a. so as to exert a thrusting force on the upper knife from said upright wall through the two eccentrics 91 and 96.

With the carriage mechanism just described, it will be understood that the knife blades carried thereby may be withdrawn bodily from the vicinity of the work by means of the fluid cylinder 1| and its position 19, which actuates the rocking lever 14, so as to give easy access to the chuck members 25 and Z6 for insertion or removal of the tread links. Simultaneously with the rearward withdrawal of the carriage with its knives, the fluid piston cylinder 18 also withdraws the left hand holding member 55 of the chuck through the lever 61, yoke 9|, collar 62 and rod 68, as previously described, so as to position the left hand holding member 55 either for receiving a tread link prior to the scarflng operation, or for the release of a tread link after the scarng operation has been completed.

The uid control mechanism for the fluid cylinders 1| and |00 is shown diagrammatically in Figure 19. 1la and l 09a indicate two master control valves of a well-known commercial type, which are designed to supply air pressure in the usual manner to opposite ends of the cylinders 1l and I 98 respectively. These master control valves are designed for'operation either by bleeding or supplying air at one end or the other. Varying the air pressure at one end of the master valve piston causes the valve to be set so as to supply pressure to one end of the power cylinder with whichit is associated and relieve the pressure from the other end of said cylinder, while varying the air pressure at the opposite end of the master valve piston reverses the operation of the power cylinder, in the usual manner.

In the arrangement shown in the diagram, the two master control valves 11a and mila are supplied with iiuid pressure from a main line |02. The master control valve 'lla for cylinder 1I, which controls the movement of the knife carriage 12 and the operation of the chuck holding or clamping member 20, as previously described, is controlled for operation in one direction by a manually operated bleeder valve |04, which is conveniently mounted on the bed plate 2 This bleeder valve |54 shown is of the pressure operated type, receiving pressure from the main line |52 through line |03 and branch line |03a. A line |04a from said bleeder valve leads through branch line |5412 to the left end of master control valve l Ia so as to set the latter valve for moving the piston l toward the left for clamping the work, and simultaneously advancing the carriage 'l2 toward the work, when the bleeder valve |04 is normally operated.

The bleeder valve |04 is also connected to the left side of the master control valve la by lines illa, |040, so as to set the latter valve for moving piston l0! in cylinder |00, thereby proiecting the lower knife 85 forwardly into scarng position, while retracting the upper knife 86, when'the bleeder valve |04 is operated.

A second bleeder valve |55 is connected through line |0511 to the right side of master control valve laila. This bleeder'valve is automatically actuated by a cam member |06 mounted on a cam drum 21a, which is xed on the right end of the chuck spindle 2l, as shown in Figure 5, so as to rotate in timed relation with the chuck members 25 and 25. Said cam is designed to operate the bleeder valve |55 when the work reaches a predetermined position, at which its scarng operation in the clockwise direction has been completed, and rotation of the work is automatically reversed by an electric control mechanism to be hereinafter more fully described. Operation of the bleeder valve sets the master control valve |050. so as to reverse the position of the piston lill in cylinder |50, `thereby causing the lower knife S5 to be retracted and the upper knife 55 to be automatically advanced into position for making the scarng cut in a counterclockwise direction.

A third bleeder valve |01 located on the bed plate 2| adjacent valve |54 has a line l'la connected to the right side of the master control valve lla. Operation of valve lill causes the last-named master control valveto be set in position to withdraw the piston 'l0 in cylinder 'l toward the right, thus releasing the work from the chuck members, and `simultaneously withdrawing the carriage l2 from the work.

The control mechanism for starting, reversing or stopping the electric motor 4| so as to rotate the work in its proper cycle for scarng is shown in the electric diagram, Figure 18. The motor is of the three-phase reversible type, operated from main supply lines H0, and H2. A remote control reversing switch unit of the magnetic type is indicated generally at i3, including three main line conductors H4, ||5 and H5, adapted to be connected reversely with the motor leads |476, lill and H9 by two sets of reversing contacts |20, |2| and |22, and |23, |24 and |25, respectively.

The contacts |20, |2| and |22 which connect the motor for forward rotation (to rotate the work in a clockwise direction, as seen in Figures 12 and 1.3) are arranged to be closed by a magnetic coil |30. Said coil also closes an auxiliary contact in the control circuit. The contacts |23, |24 and |25 which connect the motor for rotation in the reverse direction, are arranged to be closed by `a magnetic coil |3|. The latter coil also cl-oses an auxiliary contact |27 in the control circuit.

A manual control switch panel is indicated generally at |35, and is provided with a plurality of push-button control contacts |36, |37, |38 and |39. Two cam-controlled snap lock limit switches, indicated at |40 and |4I, are also provided. Switch |43 has a contact member |42, thrown by an arm |43 under control of a cam member |44 on a cam drum 27a, fixed on the outer end of the chuck spindle 21, as seen in Figure 5. Switch i4! has a Contact member |45, thrown by an arm |46 under control of a cam member |41 on the cam drum 21a.

The magnetic reversing switch ||3, the push button control switches |36, |31, |38 and |39, and the snap lock limit switches |40 and |4| are all of well known constructions, so need not be shown in greater detail, excepting to point out the various circuit connections which provide control of the operation of the motor during its normal operating cycle, as well as manual control means for modifying its normal operating cycle, when desired.

In the initial or starting position of the work as shown in Figure l2, the several manual control contacts on the control panel |35 are normally maintained by spring pressure in the positions shown in the diagram, Figure 18. The forward and reverse coils |38 and I3! will be deenergized, and the main line contacts associated therewith will be open.

The motor is started in its forward direction to rotate the chucks in a clockwise direction, by depressing momentarily the push-button contact |36 on panel |35. Said button may, for convenience, be referred to as the starting button. This establishes a control circuit from the main line conductors through the forward coilv |30, as follows: from main conductor ||6 through line |50, button contact |39, line |5 limit switch contact |42, line |52, button contact |35, line |53, contact l3, line |54, forward coil |30, line |55, limit switch contact |45, and line |55 to main line conductor I5.

Energizing of the forward coil |30 will close the main line contacts |20, |2| and |22, to start the motor in its forward direction. As soon as the motor starts, cam |44 of limit switch |40 releases the arm |43 so that switch Contact |42 is shifted to the right. Since auxiliary contact |25 is now closed by forward coil |30, a second or holding current is established through said forward coil |30, as follows: from contact |42 of limit switch |40, through line |57, button |33, line |58, contact |26, lines |59 and |53, contact i3?, line |54, forward coll |30, line |55, limit switch contact |45, and line |56, to main line conductor I5. It will be observed that as soon as this second or holding circuit is established, the starting button |35 may be released and returned to its initial position.

The motor will then continue its rotation (unless interrupted by operation of certain manual control buttons, as will hereinafter be described) until cam |41 of the limit switch |4| trips arm |46 and throws contact |45 to the right. This movement causes automatic reversal of the motor in the following manner:

The holding circuit, through contact |45, is broken, causing the main line contacts |20, |2| and |22 to open. A new circuit is now established through the reverse coil |35 as follows: from lines |50v and |5|, through contact |42, line |57, button contact |38, line |60, contact |45, lines IBI and |52, reverse coil |3|, and line |63, to main line conductor IE5. The reverse coil then closes the main line contacts |23, '|24 and |25 to rotate the motor in its reverse direction, and also closes the auxiliary contact |21. This latter contact then establishes a holding circuit from lines |58 and |5|, through contact |42, line |51, button |38, lines |58 and |64, contact |21, reversal coil |3|, and line |63. Shortly after the motor is reversed, and the holding circuit established, the contact |45 of limit switch 4| is returned to its initial position because of disengagement with its cam |41. The motor then continues rotation in reverse direction until it is automatically stopped at its initial starting position, wherein the cam |44 of limit switch |48 engages arm ,|43 and throws contact |42 tothe left, thereby breaking the holding circuit. The motor then stops v in its initial starting position, ready to be started in another cycle, by depressing the starting button, as before described.

To insure against overrunning of themotor in either direction, the friction brake 46' on the motor shaft is normally set by a spring 49d, but the tension of said spring is overcome by a coil |18, connected across the main motor leads ||8 and H9, whenever the motor circuit is closed in forward or reverse. However, the brake is mmediately set by the spring 49a as soon as the motor circuit is broken.

The manual control buttons |31, |38 and |36 are providedto afford greater facility and safety by depressing the jog button |38 partially, the i holding circuits which may have been established through said button, in a forward direction, as previously described, will be broken so as to stop the motor temporarily. When said jog button is further depressed so as t0 connect lines |51a and IE5, it will be seen that a circuit will be established through line |65, contact |36, lines |66 and |53, contact |31 and the forward coil |38, under direct manual control of the jog button, and forward rotation will continue until the reversing limit switch contact |45 is automatically shifted to the right by cam |41.

It will further be observed that it is possible to stop and reverse the chuck members at will while they are normally rotating in either direction. Such reversal is sometimes found desirable where a link may be jammed in such position through accident that further rotation in the same direction would cause damage to the machine. When the motor is rotatingr in its normal forward direction, reversal may be effected by depressing the jog button |38 partially, and shifting the control button |31. into its reversed position toward the right. Further depression of the jog button will then complete a circuit through the reverse coil |3| by way of lines |61 and |62, instead of through the forward coil |36.

When the motor is being rotated in reverse direction during normal operation, it may be backed up or run in a forward direction. This is accomplished by depressing the jog button temporarily. This will break the holding circuit through the reverse coil |3| and contact |21, to stopthe motor. Further depression of the log buttonwillthen establisha new circuit through the forward coil |30 by Way of lines |65, |66 and |53, to cause the motor to rotate forwardly. It will be understood, however, that for normal,k operation the button |31 should be maintained in its forward position toward the left.

The jog button |31 may also be used to start the motor in case the other controls fail teinporarily to work properly.

The stop button |39 is intended primarily for use as a stop in case of emergency. It opcrates immediately to break all control circuits to either forward or reverse coils and stop the motor, regardless of the positions `of the other control devices.

The operation of the machine may now be described as follows:

The starting position of the chuck members 25 and 26 is such as to hold the tread link substantially in the position shown in Figure 12. In this position, the U-shaped holding members 48 and 55 carried by the chuck members have the open ends of their slots 49 and 55a, respectively, extending upwardly and inclined slightly toward the front of the machine in position to receive the projecting pivot pins l5, I5 of the tread link in sliding engagement therein.

In this starting position, the iiuid control system will be set by the Iclamp. release valve |81, 4so that the piston 18 associated with the uid cylinder 1| has withdrawn the holding member 55 of the chuck 26 towards the left, and the carriage 12 is withdrawn to its forwardmost position. When the tread link is dropped into position between the holding members 65 and 48', the clamping lever |84 is actuated so as to extend the piston .1li in cylinder 1|, thereby chucking the work securely between the holding members with the opposite projecting ends of the lowermost pivot pins I5, l5, and the lower cylindrical member held in centered relation with the chuck members. Simultaneously, operation of :the piston4 1U causes the carriage 12 with its knives to be moved rearwardly of the machine toward the centered frame member of the work. L

Operation of the clamping lever also causes the lower cutting knife 85 to be projected forwardly into cutting position, as .shown in Figure l2, so that the blade 9| of said lower knife is disposed at a cutting angle toward the adjacent end of the tread link, and will be forced into engagement with the tread surface of the latter along the line opposite the lower or centered tubular member where the rubber covering is thinnest.

The electric motor 4| is then started by depressing the starting button |36 momentarily, as previously described in connection with the description oi' the electric system illustrated in Figure 19. The motor then rotates the tread link in a clockwise direction, as indicated in Figure 13. Pressure applied from iuid cylinder 1| causes the lower knife blade Si to cut immediately through the relatively thin rubber covering into direct scraping or scariing contact with the surface of the centered tubular member of the work.

As soon as the motor is started, the cam |44 releases arm |43 of the limit switch |48 so as to shift the contact |42 toward the right (see Figure 18). This establishes a holding .circuit for the forward coil |30 so that rotation of the work in a clockwise direction is continued until the work reaches a position substantiallyias shown in fulllines in Figure 13. At this pointr'otation is stopped byactuation of the limit switch |4| by cam |41,'which breaks the holding circuit through ,the lforwardcoil |30, and automatically reverses the rotation of the work throughV the circuit connections previously described.

It will be observed that when the work reaches its reversing position shown in Figure 13, the lower knife 85 will have produced a scarfing cut circumferentially around the outer end of the tubular member and will be projected inwardly between the two tubular members II, II, to a line adjacent the median plane including the `aXes of said tubular members. Although in some instances the scariing maybe extended to said median plane, yet it is usually preferable to leave a relatively small area adjacent the median plane uncut and depend upon a subsequent punching operation for nal removal of theruober or block, as will hereinafter be described.

Substantially simultaneously with the automatic reversal of the motor through the electric control system as previously described, the cam member |65 associated with the fluid control system actuates the bleeder valve |65 so as to retract the lower knife 85 and advance the upper knifev 86 into cutting position, as indicated in Figure 14. Thereupon, further rotation of the work in a reverse or counterclockwise direction causes the blade 92 of the upper knife 85 to -contact the adjacent surface of the tubular member I I in the area which has previously been scarfed by the lower blade 9|, but at a reverse angle thereto, as shown in Figure 14. The lower blade 9| thereafter completes the scarng cut circumferentially around the previously uncut tubular member until the tread link reaches its starting position, substantially as shown in dotted lines in Figure 13. f

It will be observed in Figure lll, that the arcuate portion of rubber already severed from the tubular` member II will be held away from the latter by the lower blade 9| during the return rotationof the work, so that said severed portion of rubber vcannot interfere with the scarng by the upper blade 92.

When the work reaches the starting positio after reversal in a counterclockwise direction, the limit switch Il is actuated so as to stop the work automatically. As in the case of the lower blade 9|, the arrangement is such that the upper blade 92 may out almost to the median plane including the axes of the two tubular members II, II, so as to form substantially a complete cut around the first tubular member, excepting as to .a small area of unscarfed rubber which may be left along the inner side of said member to be severed by a subsequent operation.

When the work has reached its starting position, and its normal cycle of operation is completed, the work may then be released by operation of the release valve lill of the fluid control system, which causes the work to be unclamped in the chuck members and the ram 'I2 with its knives to be withdrawn rearwardly from the work.

When the holding member 55 of the chuck 26 is withdrawn to the left to release its clamping pressure on the end of the tread link, the knockout pin 52 moves the opposite end of the tread link to the left, to release the proximate ends f pivot pins I5, I from recesses 5i] and 5I in the holding member d8. The tread link can then be readily lifted from between the holding members 48' and 55.

The scarng operation thus described may then be repeated on the second tubular member |I of the same link, in the same manner. yIt is usually preferable, however, that said link be reversed end to end when it is removed and replaced between the chuck mmbers, so that when the second tubular member is centered between the chuck member, the lower blade will make its initial out on the same side or tread surface of the link as itdid with the first tubular member. As a result, the final parting lines or cuts opening to both tubular members II, I I `will be 1ocated along the same tread surface of the link, as clearly shown in Figure 2, so as tofacilitate the iinal removal of the severed rubber block. This maynow be readily accomplished in any suitable manner. A preferred method consists in engaging the area between the two lines of cut by a suitable punch, whereby the rubber block can be removed from between and Varound the tubular members. This punching operation will effectively sever any unscarfed portions which may remain in the limited areas between the two tubular members, as previously described.

It will be understood from the above description that the normal cycle of operation of the machine consists in starting .the motor by manual operation o-f the starting button |35, so that the work rotates forwardly through an angle of approximately 240 degrees in aclockwise direction, stops, reverses automatically, and rotates in a counterclockwise direction to its starting position, where it is stopped automatically. rIt will be understood, however, that this normal cycle may be modified when desired or necessary by manual operation of the jog button |38, the forward and reverse button |37, or the emergency stop button |39 on panel I 35, as previously described in connection with the. description of the electric control system shown in the` diagram, Figure 18.

It will be observed that the lever B'I and link "I3 cooperate with the piston rod I0 of the fluid cylinder 'II so as to form in eiect a to-ggle arrangement for causing the simultaneous advance and withdrawal of the carriage 'I2 with its knives and the advance or withdrawal of the holding member 55 of the chuck 26, as previously described.

Although I have shown and described a preferred embodiment of my invention, it is to be understood that I do not wish to be limited to the exact embodiment of the device shown, which -is merely by way of illustration and not limitation, as various other forms of the device will, of course, be apparent to those skilled in the art without departing from the spirit of the inven-l tion and scope of the claims.

I claim: f

l. In a scarng machine for stripping a rubber block from a rectangular metal frame of a tread link or the like having two spaced parallel cylinrical members between and around which said rubber block is molded, said machine including reversibly driven chuck means,holding means on said Vchuck means for securing said frame with one of the cylindrical members thereof centered in said chuck means, knife supporting means movable radially of said chuck means, and power means operative to move said holding means and said knife supporting means' simultaneously into and out of operating engagement with said centered cylindrical member.

2. In a scari'ing machinefor stripping a rubber block from a rectangular metal frame of a tread link or the like having two spaced parallel cylindrical members between and around which said rubber block is molded, said machine including two reversibly driven, opposed chuck members,

other on each of said chuck members, each having slots extending radially of the latter and open .at their outer ends to receive the opposite ends of said frame in sliding engagementtherein, one

vof said holding members being axially movable in its chuck member to clutch the opposite ends of said frame within the slots of said'holding members.

3. In a scarng machine forstripping a rubber block from a rectangular metal frame of a tread link or the like having twoispaced parallel cylindrical members between and around which said rubber block is molded, said machine including two reversibly driven, oppc-sed chuck-members, holding members mounted on each of said chuck members, each having slotsextending radially of the latter and open at theiry outer ends to receive Athe opposite ends of said frame in sliding engagement therein, one of said holding members being axially movable in its chuck member, and

the other of said holding members being recessed to receive an end portion ofsaid frame in laterally tting engagement therein with one of the cylindrical members of said frame in centered relation to said chuck members when the opposite holding member is in advanced position.

4. In a scarring machine for stripping a rubber block from a rectangular metal frame of a tread link or the like having two spaced parallel cylindrical members between and around which said rubber block is molded, said machine including two reversibly driven, opposed chuck members, holding members mounted on each of said chuck members, each having slots extending radially of the latter and open at their outer ends to receive the opposite ends of said frame in sliding engagement therein, one of said holding members being axially movable in its chuck member, and the other of said holding members being recessed to receive an end portion of said frame in laterally fitting engagement therein with one of the cylindrical members of said frame in centered relation to said chuck members when the opposite holding member is in advanced position, and spring-pressed knockout means in said recessed holding member for releasing the frame from the latter when the opposite holding member is in retracted position.

5. In a scarng machine for stripping rubber from a rectangular metal frame of a tread link or the like having two spaced parallel cylindrical members between and around which said rubber block is molded, said machine including two opposed chuck members for holding a tread link with one of its cylindrical frame members in centered position therebetween, means for rotating said chuck members reversibly in unison, a carriage guided for movement by power radially of said holding member, a pair of knife blades slidably mounted on said carriage and having their cutting edges arranged at reverse cutting angles relative to each other, and power means on said carriage for alternatively projecting said knife blades into scarring position in each direction of rotation of said chuck members.

6. In a scarflng machine for stripping rubber from a rectangular metal frame of a tread link or the like having two spaced parallel cylindrical members between and around which said rubber block is molded, said machine including two opposed chuck members for holding a tread link with one of its cylindrical frame members in centered position therebetween, means for rotating said chuck members reversibly in unison, a

,f7 .carriage guided for movement by power radially of said holding member, a pair of knife blades slidably mounted on said carriage in mutual lsupporting engagement with each other and having their cutting edges arranged at reverse cutting angles relative to each other, and power means on said carriage for alternativelyprojecting said knife blades into scarring position in each direction of rotation of said chuck members.

7. .In a scarring machine, a frame, a reversibly driven chuck on said frame, a carriage guided for movement on said frame radially of said chuck, a pair of knife blades slidably mounted one above the other on said carriage in mutually supporting engagement with each other, but having their cutting edges arranged at reverse cutting angles relative to each other, cam means on said carriage alternatively extending or retracting said knife blades relative to said carriage, and power. means for vactuating said cam means.

8. In a scariing machine, a frame, a reversibly driven chuck on said frame, a carriage guided for movement on said..frame `radially of said chuck, a pair of knife blades slidably mounted one above the other on said carriage in mutually supporting engagement with each other, but having their cutting edges arranged at reverse cutting angles relative to each other, cam means on said carriage alternatively extending or retracting said knife blades relative to said carriage, and power means operable at predetermined positions of said reversibly driven chuck member for actuating said cam means.

9. A scarl-lng machine of the character described including two opposed chuck members for holding the work in centered position therebetween, a motor for rotating said chuck members reversibly in unison, a carriage guided for movement by power radially of said chuck members, knife means carried by said carriage adjustable at reverse scarng angles relative to the work in each direction of rotation of the latter, power means on said carriage for eecting adjustment of said knife means, automatic control means for reversing the direction of rotation of said motor at a predetermined point, and control means for said last-named knife adjusting means adapted to reverse the scarng angle of said knife means automatically upon reversal of the direction of rotation of said motor.

10. A scarring machine of the character described including two opposed chuck members, holding means on said chuck members for securing the work in centered position therebetween, a motor for rotating said chuck members reversibly in unison, a carriage guided for move- Ament by power radially of said chuck members,

knife means carried by said carriage adjustable at reverse scarng angles relative to the work in each direction of rotation of the latter, power means on said carriage for effecting adjustment of said knifing means, power means operative to move said holding means and said carriage simultaneously into and out of operative engagement with said centered cylindrical member, and manually controlled means for said power means also operatively connected with said power adjusting knife means on said carriage so as to effect adjustment of said knife means automatically into predetermined scarng angle relative to the work simultaneously with the actuation of said holding means and the movement of said carriage toward the work.

1l. In a machine of the class described, a chuck, a drive motor for said chuck, reverse switch mechanism for saidmotor including a 4forward and reverse coil, a control circuit for selectively energizing said coils including two cam-operated limit switches operable in timed relation with said chuck, one of said switches being adapted to complete a circuit through said forward coil and the other limit switch between predetermined points of rotation of said chuck for rotating the .chuck forwardly, and the other switch being adapted to break said forward holding circuit at another predetermined point and to complete the second holding circuit through said reverse coil and the first-named limit switch for rotating said chuck reversely until said second limit switch is actuated to break said reverse holding circuit and stop the motor, a manually-controlled switch member for starting said motor in its forward direction, a second manually-controlled switch member normally closing both of the holding circuits established by said limit Switches, circuit connections from said second 'manually-controlledswitch member and selectively operable" by the latter including a third manually-controlled switch member selectively operable to .establish a circuit at will through the forward or reverse coils, whereby said second manually-controlledy switch member may be operated to break the normal holding circuits at will to stop the motor and establish a circuit through either the forwarder reverse coil. Y

12.r Inl a machine of the character described including a frame, reversely driven chuck means supported on said frame, axially movable holding means on said chuck means for securing the work in the latter, knife supporting means movable-radially of` said chuck means,y and power means on said. frame operative to move said holding means and said knife supporting means simultaneously into and out of operative engagement with the. work, said power means including a. cylinder' and piston and toggle members actuated by said piston and connected respectively' withsaid holding means and saidv knife supporting means.

RAY A. SANDBEJRG.l 

